Backpack



FIG. 1 is a top front perspective view of a backpack showing the claimed design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is an enlarged front side perspective view of a portion of the backpack shown in FIGS. 1-7, with a portion of the backpack in an open configuration showing interior details of the design.

The dashed broken lines in the figures show portions of the backpack that form no part of the claimed design.

The dot-dash broken lines in the figures show boundaries that form no part of the claimed design. 

CLAIM The ornamental design for a backpack, as shown and described. 